Lighting devices are used for various purposes. For example, lighting devices may be used for backlight units (BLUs) of displays such as a liquid crystal display (LCD), a TV, a computer, a mobile phone, a smart phone, a personal digital assistant (PDA), a gaming device, an electronic reading device, and a digital camera. Also, the lighting devices may be used for interior or exterior lighting, stage lighting, decorative lighting, accent lighting, museum lighting, or specific wavelength lighting necessary for horticulture or biology.
As a lighting device, for example, there is a device emitting white light by a combination of phosphors such as a blue light-emitting diode (LED) and a yttrium aluminum garnet (YAG) used as an LCD BLU.